XMLSpear, a free XML editor, is available. Experiential XML users will appreciate the advanced features of validating files. The text editor included in the package is usefull to edit plain text files (shell scripts and config files, as well as.plist files, etc.).
Version 3 introduced important new features like:
Version 3.40:
Note: Now requires OS X 10.7.3 or later running on a 64-bit Intel processor